Web3 developer platform Thirdweb disclosed a major security vulnerability discovered in its open-source library.

This vulnerability, which Thirdweb became aware of on Nov. 20, affects multiple NFT collections — specifically, pre-built smart contracts it provided. However, the firm has not clarified which specific collections may be impacted.

One of the largest NFT trading platforms, OpenSea, came forward in response — noting that some NFT collections on its platform were impacted. OpenSea said it's working with those collections to mitigate security issues. "We are in touch with Thirdweb about the security vulnerability impacting some NFT collections. Stay tuned for more info on how we can assist affected collection owners with any changes on OpenSea tied to contract migration," OpenSea